Immune deviation induced by ocular antigen presenting cells involves a protective peripheral immune response that prevents inflammation. Such anti-inflammatory immune response plays a significant role in avoiding potentially blinding effects of ocular inflammation. The unique ability of ocular APCs to induce such a protective response is attributed to their exposure to TGF-2 in their local microenvironment. Studies described in this proposal seek to elucidate molecular mechanisms utilized by such TGF-2-exposed APCs in inducing a regulatory immune response. The first specific aim seeks to determine the significance of thrombospondin-1 (TSP-1) in the induction of a peripheral population of regulatory T cells. Since we demonstrated earlier that TSP-1 is essential for ocular immune privilege, experiments in this aim will allow us to determine the effect of TSP-1 on peripheral immune effectors. The second aim seeks to investigate the specific contribution of the interactions of TSP-1 with its receptors on the effectors, which subsequently suppress inflammatory immune response. Considering the multidomain structure of a large molecule like TSP-1 with multiple cell type specific biological effects, these investigations will clarify mechanisms by which TSP-1 contributes to immune deviation. The final aim addresses the relevance of TSP-1 dependent mechanisms in regulation of autoimmune ocular inflammatory conditions as seen in experimental autoimmune uveitis (EAU) and Sjogren's syndrome associated ocular surface disease dry eye. Since TSP-1 is known to be important in maintaining immune privilege these studies will allow us to evaluate if application of any of the TSP-1 dependent mechanisms can help resolve chronic ocular inflammatory diseases. Together these studies can build further on the existing knowledge of ocular immune responses and provide insights into novel therapeutic strategies.